Rheostat



July 30,1935. c. E. BERGER RHEOSTAT Filed Sept. 5, 1933 3 Sheets-Sheet 1 JW 'BY'CLARKNCE E. BERGER,

c. E-. BERGER 2,009,380

RHEOSTAT Filed Sept. 5, 1935 3 Sheets-Sheet 2 July 30, 1935.

July 30, was. 5. E. BERGER 2,00 380 RHEOSTAT Filed-Sept. 5, 1933 3 Sheets-Sheet 3 CLARENCE LBERGER,

@douw Patented July 30, 1935 2,009,380

UNITED STATES PATENT OFFICE RHEO STAT Clarence E. Berger, Shrewsbury, N. J., assignor to Hanson-Van Winkle-Munning Company, Matawan, N. J.

Application September 5, 1933, Serial No. 688,132

15 Claims. (01. 201-48) This invention relates to improvements in rheoconnected to the other terminal of the rheostat. stats, and has for its object to provide a rheostat When such a short-circuiting switch is used the in which the switches are reduced in length and ammeter shunt so connected is also short cirare of heavier copper to prevent the bending of cuited to D fi t damage to the fl terthe blades or jaws when side pressure isapplied. These and other advantages will appear from 5 It is an object of this invention to provide, in the following description taken in connection with connection with rheostats, resistors that are inthe drawing closed in a case which is open at its top and bot- -R rr g t0 e draWiIlgSI tom, whereby a cooling draft is produced. The Figure 1 is a top plan view of the panel with case is also used for mounting purposes. the case mounted thereon and the various rheo- 10 It is also an object of this invention to provide, Stat e em s s pp t on the Panel and 011 the in connection with a case inclosing resistors, a panel within the case. battle between the resistors and a panel supporting Figure 2 is a section on the line 22 of Figure 1. the case to prevent the heat of the resistors from Figure 3 is a e ion On the line of Figure radiating to the panel and heating the various in- Figure 4 is a front elevation of the rheostat. strumentalities that are supported on the panel. F gure 5 iS a ectio 011 the line 5 of Figure It is an object to provide resistors adapted to gure 6 is a cti Onthe line of Figure carry heavier currents, the resistors being diag- The supporting and protective features of the onally mounted to prevent the concentration of pr nt rh at onsist of a pa el I d a se the heat at any one point of the panel. mounted upon the panel for inclosing the parts 20 It isafurther object of the invention to provide of the rheostat. Thiscase is composedof two resistor supports, consisting of thin strips of metal sides 2, and a back 3 attached to the panel by to prevent the heat of the resistor from being means of lateral flanges 4 0n the Sides, and transmitted to the switches and to provide a bolts 5 passing through the flanges and the panel.

broader surface for heat radiation. These sup- Some of the bolts for holding the case on the 25 ports also prevent the breaking of the resistor panel are provided with spacers 6 for supportstrips. ing on the bolts in spaced relationship with the It is the object of the invention to provide a panel, a baffle plate 1 held on the spacers by design for mounting strips for resistors of large means of nuts 8.

v capacity wide enough to voffer maximum cooling Connected to the panel at the top thereof, and 30 area and thin enough to retard the transmission between the panel and the back 3, is a conductor of heat but not 'thin enoughto develop a material bar 9 adapted to be connected to the negative amount of heat by their own resistance. of a main line. Fastened to this conductor bar,

By utilizing a proper proportion and by emadjacent the upper edge of the panel, is a cross bodying this proportion in nickel with a thermal conductor bar In which serves as one of the ter- 35 conductivity only 15% that of copper and a speminals for the rheostat. These two bars are atciflc resistance 440% that of copper, thereby I tached to the panel by means of a bolt H. The secure an increased width of the nickel support terminal bar is held in spaced relationship in reover that of copper giving a stronger support and gard to the panel by means of the *conductor 40 more radiating surface and, at the same time, the bar 9. 40 nickel has 15% ofthe thermal conductivity and The conductorbar 9 is also attached to the 23 of the electrical conductivity of copper. panel by means of a bolt 12 which passes through It is afurther object to provide a master switch the panel and through a plate I3 on the outto open the circuit to the tank without the neside of the panel for holding the plate to the oessity of opening a number of small switches. panel. This plate and conductor bar are also 5 This saves time and effort, particularly when the connected to the panel by means of a screw l4 operator is wearing rubber gloves. It reduces extending from theinside of the case, through wear and damage to the small switches and it the conductor bar, the panel and into the plate enables the operator to disconnect the tank for l3. On the plate I3 is a pair of contact jaws loading and unloading and reconnect it without l5, each of which has a flaredcorner I6 for 50 changing the rheostat setting, thereby insuring readily receiving the blade of a switch. duplication of results. In line with the conductor bar '9 is a con- It is a further object to be able to provide a ductor bar ll adapted to be connected to the short circuiting switch where necessary by prowork rod used for supporting the work in electroviding another pair of jaws for the master switch plating. Opposite the conductor bar 11, on the 55 tween the ofiset part of the conductor bar ii and the panel is a cross conductor bar or rheostat terminal 22, held on the panel by means of bolts 23. There are seven of these bolts 23 extending through the cross conductor 22 and the panel from one end of the bar to the other.

Cooperating with these bolts are screws 2d for attaching a plurality of plates to the panel on the outside of the case. These plates are designated 25, 2t, 2?, 28, 29 and 30. Each of these plates has extending upwardly therefrom a pair of posts 3|, which pivotally support a contact blade 32 pivoted at one end to the posts. The contact blades are adapted to fit between contact jaws 34, each of which has a flared corner 35 for,read ily receiving the blade. supported on plates 36, attached to the panel by means of bolts 37, 31a, 31b, 31c, Sid and 31e, in cooperation with screws 38, one screw for each bolt. Each blade 32 has a handle 33.

The bolt passing through the rheostat terminal.22 and the panel, beneath the ofiset part of the ,conductor bar ii, is designated by the numeral 40, which has cooperating therewith a screw il for holding a plate 39 upon thepanel halfway between the ends of the rheostat terminal 22. Extending upwardly from the plate 39 "is a pair of jaws 52, each of which has a flared the contact jaws it. When the blade 4 3 engages the contact jawsifi the resistance elements are all cut out. When the blade Mi engages the contact jaws 52 the various resistance elements may be cut in by operating the blades 32. Attached to the terminal 80 of the rheostat is a plurality of thin strips made of any suitable met- -al, preferably nickel. These strips prevent the heat of the resistors from being transmitted to the switches. I It has been found by experiment that by mounting the resistors on thin strips of a proper material and oi proper size, the temperature rise at the switches is reduced one-third of that obtained when the resistors are mounted on heavy studs. These strips afiord a wide cooling area, and are thin enough to retard the transmission of heat but not thin enough to develop much heat by their own resistance. At the top of the panel and extending across the inside of the panel on the terminal of the rheostat are five of these strips, 41, 48, 49, 50 and 5!, attached to the terminal by means of bolts 52.

Connected to the strip 41 is a resistance coil 53, which is also connected to a strip 54 attached to the panel by means of the bolt 31c. Attached to the strip '48 is a resistance coil 55, which EX:-

tends to and is attached to a strip 56 supported These contact jaws are the panel by means of the bolt 37. A resistance plate 59 is attached at one end to the strip 50,- 'while its other end is attached to a strip 60, sup-.

ported. on the panel by means of the bolt 31a.

A resistancepoil ti is attached at one end to the strip 5|, while its other end is attached to a strip 62, supported on the panel by means of the bolt 37b. Attached at one end to the strip 5! is a resistance coil 63, which is attached at its other end to a strip 64 supported on the panel by means of the bolt t le.

It will be observed from an examination of Figure 2 that the various resistance elements extend diagonally across the panel, with the exception of the resistance coil 63. By this means the heat from the resistance elements is fairly'well distributed through all parts of the space'inclosed within the case. It will be observed from anexamination of Figures 2 and 5 that between these resistance elements and the panel is the bafile i, which tends to protect the panel and the elements located thereon from the effect of the heat produced by the current passing through the resistance elements.

The various bars, plates, posts, switch blades and contact jaws are made of copper and serve as conductors for electricity. The strips are made 'of some suitable metal, such as nickel, while the resistance elements are made of some highly re sistent metal.

Located on the outside of the panel is an ammeter 65,- which has extending therefrom a conductor 69 for, connecting the ammeter to an ammeter shunt -plate ti at the point 68. There also extends from the ammeter a conductor 66, which is attached also to the conductor 22 at the point id This plate 67 is supported in spaced relationship with the terminal 22 and is insulated at one end from the terminal by means of a washer ii, through which the bolt 4t passes.

"The plate 67 is connected in the manner shown in Figure 6 so that the only connection between the terminal 22 and the plate 33 is through it and the current resistors on the ammeter. When the master switch is closed upward to short circuit the rheostat. there is no current through the shunt plate 61. The shunt plate may be mounted in a similar manner between the conductor bar 9 and the conductor bar it). When no'short circuitingswitch is used the shunt plate 67 may be mounted at any point in the circuit,

preferably on the member 9 or 2i to serve as a connection from either'member to the bus bar. In this case the plate39 and the terminal 22 are connected solidly by the bolt ill. There is also mounted on the panel a voltmeter i2, which has extending therefrom a conductor i3 adapted to be connected to the work rod, and a conductor M adapted to be connected to the anode rod.

When a current of electricity is passing through the resistance elements the heat therefrom is distributed through the space between the back 3 and the baflle 1 because of the diagonal arrangement of the resistance elements and because of the fact that these elements are not in alignment with each other, some being closer to the bafie than others. The heat created by the resistance elements causes a draft through the case. This draft through the case, between the bafile i and the back 3, creates also a draft of cold air between the panel and the bafile 1, thereby keeping the panel'cool and all of the elements supported on the panel without the case cool.

While the conducting elements are generally copper or brass, other metal may be used, and

other metals than nickel may be used as supports for the resistance elements.

It will be understood that I desire to comprehend within my invention such modifications as second rheostat terminal bar attached to the panel 7 adjacent the other conductor bar, a plurality-of resistance elements, each connected at one end to the firstnamed rheostat terminal bar and at its other end ,0 the panel, means to electrically connecteach of the other ends of the resistance elements to the second rheostat terminal bar, and means to electrically connect the conductor bars and to connect said other conductor bar to the second rheostat terminal bar.

2. In a rheostat, alpanel having on one side a pair of aligned spaced conductor bars, a rheostat terminal bar connected to one conductor bar, a second rheostat terminal bar attached to the panel adjacent the other conductor bar, a plurality of resistance elements, each connected at one end to the first-named rheostat terminal bar and at its other end to the panel, switches to electrically connect each of the other ends of the resistance elements to the second rheostat terminal bar, and a switch adapted in one position to electrically connect the conductor barsand adapted in another position to connect said other conductor bar to the second rheostat terminal bar.

3. In a rheostat, a panel having on one side a pair of aligned spaced conductor bars, a rheostatterminal barattached to one conductor bar, a second rheostat terminal bar attached to the panel and out of contact with the other conductor bar, a plurality of resistance elements, each connected at one end to the first-named rheostat terminal bar and at its other end to the panel, switches to electrically and selectively connect each of the other ends of the resistance elements to thesecond rheostat terminal bar, and a switch adapted in one position to electrically connect the conductor bars and adapted in another position to electrically connect said other conductor bar to the second rheostat terminal bar.

4. In a rheostat, a panel having on one side a pair of alignedlspaced conductor bars, a rheostat terminal bar attached to one conductor bar, a

' second rheostat terminal bar attached to the panel and out of contact with the other conductor bar, a plurality of resistance elements, each connected at one end to the first-named rheostat terminal bar and at its other end to the panel, switches to electrically and selectively connect each of the other ends of the resistance elements to the second rheostat terminal, a switch adapted in oneposition to electrically connect the conductor bars and adapted in another position to electrically connect said other conductor bar to the second rheostat terminal bar, and means to protect, the panel and the switches from the heat of the resistance elements.

5. ma rheostat, a panel having on one side a pair ofalignedspaced conductor bars, a rheostat terminal bar attached to one conductorbar, a second rheostat terminal bar attached to the panel and out of contact with the other conductor bar, a plurality of resistance elements, each connected at one end to the first-named rheostat terminal bar and at its other end to the panel, switches to electrically and selectively connect each of the other ends of the resistance elements to the second rheostat terminal bar, a switch adapted in one position to electrically connect the conductor bars and adapted in another position to electrically connect said other conductor bar to the second rheostat terminal bar, and means to protect the panel and theswitches from the heat of the resistance elements, said means comprising a baffle plate between the panel and the resistance elements.

6. In a rheostat, a panel having on one side a pair of aligned spaced conductor bars, a rheostat terminal bar attached to one conductor bar, a second rheostat terminal bar attached to the panel and out of contact with the other conductor bar, a plurality of resistance elements, each connected at one end to the first-named rheostat terminal bar and at its other end to the panel, switches to electrically and selectively connect each of the other ends of the resistance elements to the second rheostat terminal bar, a switch adapted in one position to electrically connect the conductor bars and adapted in another position to electrically connect said other conductor bar to the second rheostat terminal bar, and means to protect the panel and the switches from the heat of the resistance elements, said means comprising a casing around the resistance elements and a bafiie plate within the casing between the resistance elements and the panel.

'7. In a rheostat, a panel having thereon a pair of aligned spaced conductor bars, arheostat terminal har attached to one conductor bar, a second rheostat terminal bar attached to the panel out of contact with the other conductor bar, a plurality of nickel strips attached to the first-named terminal bar, a plurality of nickel strips attached to the panel, resistance elements connecting the first-named strips to the second-named strips, and means to electrically connect the conductor bars directly or through the resistance elements.

8. In a rheostat, a panel having thereon a pair of aligned spaced conductor bars, a rheostat terminal bar attached to one conductor bar, a second rheostat terminal bar attached to the panel out of contact with the other conductor bar, a plurality of nickel strips attached to the first-named terminal bar, a plurality of nickel strips attached to the panel, resistance elements connecting the first-named strips to the second-named strips, and means to electrically connect the conductor bars directly or through the resistance elements, saidresistance elements being arranged in groups with the elements of one group extending across the elements of another group.

9. In a rheostat, a panel having thereon a pair of aligned spaced conductor bars, a rheostat terminal bar attached to one conductor bar, a sec- 0nd rheostat terminal bar attached to the panel out of contact with the other conductor bar, a plurality of nickel strips attached to the firstnamed terminal bar, a plurality of nickel strips attached to the panel, resistance elements connecting the first-named strips to the secondnamed strips, means to electrically'connect the conductor bars directly or throughthe resistance elements, and means to protect the panel from the heat of the resistance elements.

10. In a rheostat, a panel having thereon a pair of aligned spaced conductor bars, a rheostat terminal bar attached to one conductor bar, a second rheostat terminal bar attached to the panel and out of contact with the other conductor bar, a plurality of nickel strips attached to the first-named terminal bar, a plurality of nickel strips attached to the panel, resistance elements connecting the first-named strips to the secondnamed strips, means to electrically connect the conductor bars directly or through the resistance elements, and means to protect the panel from the heat of the resistance elements, said means comprising a plate supported between the panel and the resistance elements. V

11. In a rheostat, a panel having thereon a pair of aligned spaced conductor bars, a rheostat terminal bar attached to; one conductor bar, a second rheostat terminal bar' attached to the panel out of contact with the other-conductor bar, a plurality of nickel strips attached to the firstnamed terminal bar, a plurality of nickel strips attached to the panel, resistance elements con- -minal bar attached to one conductor bar, a second rheostat terminal bar attached to the panel out of contact with the other conductor bar, a plurality of nickel strips attached to the firstnamed terminal, a plurality of nickel strips attached to the panel, resistance elements extending, diagonally of the panel and connecting the strips, and a switch adapted in one position to electrically connect the conductor bars directly and adapted in another position to connect the conductor bars through the second rheostat terminal bar and the resistance elements.

13. In a rheostat, a panel having thereon a pair of aligned spaced conductorbars, a rheostat terminal bar attached to one conductor bar, a second rheostat terminal bar attached to the panel out of contact with the other conductor bar, a plurality of nickel strips attached to the first-named terminal, a plurality of nickel strips attached to the panel, resistance, elements extending diagonally of the panel and connecting the strips, a

switch adapted in one position to electrically con; nect the conductor bars directly and adapted in another position to connect the conductor bars through the second rheostat terminal bar and the resistance elements, and means to protect the switch and the panel from the heat of the resistance coils.

14. In a rheostat, a panel having thereon a pair of aligned spaced conductor bars, a rheostat ter-- minal bar attached to one conductor bar, a second rheostat terminal bar attached to the panel out of contact with the other. conductor bar, a plurality of nickel strips attached to the firstnamed'terminal, a' plurality of nickel strips attached to the panel, resistance elements extending diagonally of the panel and connecting the strips, a switch adapted in one position to electrically connect the conductor bars directly and adapted in another position to connect the conductor bars through the second rheostat terminal bar and the resistance elements, and means to protect the switchand the panel from the heat of the resistance coils, said means comprising a plate supported between the panel and the resistance elements.

15. In a rheostat, a panel having thereon a pair of aligned spaced conductor bars, a rheostat terminal bar attached to one conductor bar, a second rheostat ter'minal bar attached to the panel out of contact with the other conductor bar, a plurality of nickel strips attached'to theflrst-named terminal bar, a plurality of terminal bars attached to the panel outof contact with the other conductor bar, a plurality of nickel strips attached to said plurality of terminal bars,v

CLARENCE E. BERGER. 

